Semiconductor package and manufacturing method thereof

A package comprising:

• a redistribution layer having a first surface and a second surface opposite to the first surface;
• a molded structure disposed on the first surface of the redistribution layer, wherein the molded structure includes a first die and a second die laterally surrounded by a molding compound, and the first and second dies are electrically connected with the redistribution layer;
• a circuit substrate connected with the second surface of the redistribution layer, wherein the circuit substrate includes a dielectric material, a cavity concave into the dielectric material and having metal-free dielectric surfaces, and a floor plate below the cavity and fully wrapped by the dielectric material;
• a third die and a fourth die, disposed on the second surface of the redistribution layer, located in the cavity and electrically connected with the redistribution layer;
• and
• an underfill, disposed between the third and fourth dies and the cavity and between the circuit substrate and the redistribution layer.

A method for forming a semiconductor package, comprising:

• providing a circuit substrate having a cavity concave from a first surface of the circuit substrate, wherein the circuit substrate includes a dielectric material, metallic patterns embedded in the dielectric material, and a metal floor plate below the cavity and fully wrapped by the dielectric material, wherein a span of the metal floor plate and a vertical projection of the cavity are overlapped, and the metal floor plate is electrically isolated from the metallic patterns and is electrically floating;
• forming conductive balls on a second surface of the circuit substrate opposite to the first surface;
• disposing a semiconductor die in the cavity, wherein the first semiconductor die is electrically connected with the metallic patterns of the circuit substrate;
• and
• forming a filling material between the semiconductor die and the circuit substrate, filling up the cavity and wrapping the first semiconductor die.